Develop · Data centre · United States
5 GW
100% green energy feasibility for an AI data centre hub
Hourly solar production profiles across 5 GW, delivered in days instead of months.
Higher Returns.
Faster Decisions.
Tomsawyer is an independent engineering firm for solar and storage. We find the highest-IRR design for every site, assess the risks before you commit capital, and forecast long-term yield from P50 to P99, at the speed of software and with the rigour of experienced engineers.
Utility-scale and C&I · Developers, investors and lenders · Pre-construction and operating assets
50+ GW
solar and storage engineered and assessed
30+ countries
in established and emerging markets
Days, not weeks
from site data to bankable results
Trusted bydevelopers, investors and advisors
Why clients work with us
We work with developers, investors, lenders and asset owners on utility-scale and C&I projects, from site screening through due diligence to operating plants. Our engineers combine industry-standard tools with our own simulation engines, run through AI workflows, and an experienced engineer reviews every conclusion.
Independent
We are not an EPC or an equipment supplier, so we have no stake in which design, equipment or contractor you choose.
Thorough
Our studies test hundreds of designs or scenarios against 20+ years of weather, not a single base case.
Traceable
Every assumption carries its source and date, so reviewers can check the model rather than rebuild it.
Responsive
Fast turnarounds, and same-day re-runs when a vendor quote, tariff or grid limit changes, so your numbers stay current through the deal.
From first screening to operating plant
Each engagement is scoped to the decision in front of you: a go/no-go, an investment committee or a lender's review.
Develop
Before you commit development capital
- Site screening and go/no-go
- Design and configuration optimisation
- Solar and BESS sizing
- Energy yield assessment, P50 to P99
- Preliminary layouts for EPC tender
For developers and IPPs, through to the brief your EPC builds from.
Acquire
Before you invest or lend
- Technical due diligence
- Red-flag reviews and risk registers
- Independent capacity and yield checks
- P50 to P99 from modelling or operating history
- Design and resource basis review for lenders
For investors, lenders and their advisers.
Operate
Once the plant is running
- Operating plant reviews
- PR and availability analysis
- Curtailment and outage assessment
- Under-performance diagnosis
- Long-term energy forecasts
For asset owners and operators.
Project types
Utility-scale solarC&I and captive solarSolar + BESSStandalone BESS
Proven results in solar and storage
Develop · Utility-scale · Australia
15.3 GWp in 3 weeks
Site-by-site pre-feasibility for a Queensland portfolio
Investors knew which projects to prioritise before committing further development spend.
Acquire · 150+ MWp · Southeast Asia
~18% less capacity
Than the developer claimed, found before the investor committed
14 red flags registered, 5 rated high.
Develop · C&I rooftop · Abu Dhabi
+4% IRR
Found just before financial close
8% lower cost and 15 kWh/kWp more yield than the client's own design.
Storage · Solar + BESS · UK
15 MW avoided
Of power conversion on a motorway services site
A 10 MW battery recovers as much curtailed solar as a 25 MW one, at the same 25 MWh.
Advisory · EPC bid review · Europe
Multi-site
EPC bidder's package review for solar farms across Europe
Independent technical comparison of competing EPC proposals for a leading global advisory firm.
Develop · Site screening · Italy
Hybrid solar
PV and hybrid renewable site screening and ranking
Early-stage feasibility assessment for a leading global advisory firm's Italian pipeline.
Advisory · DD · Africa and Middle East
>1 GWp
Automated due diligence for a global advisory firm
Batch yield re-modelling and design audits, delivered as P50/P90 forecasts.
Working on a similar project?
Tell us the site and the question. We'll figure out the analysis on a 30-minute call.
How we get you there
The highest-IRR design exists for every site. We find it early, before the design is locked and costly to change.
01
Send us what you have
A KMZ, a PVsyst file, a data room. AI agents extract the inputs. No templates to fill.
02
Every option simulated, not estimated
Layouts, equipment, BESS sizes, DC/AC ratios, each run through hourly energy and cash-flow models. No shortcut estimate decides the ranking.
03
An engineer reviews it
Our engineers apply the judgement a model can't: loss factors, uncertainty and the questions your lender will ask.
04
You brief your EPC with a target
A recommended design with full financials. Your EPC builds to a known optimum, not their first pass.
Your brief: maximise IRR, at least 2.0 MWp, capex under $1.10M
IllustrativeScreening modules, inverters and mounting0 designs simulated
| Option | MWp | Capex | IRR | Brief |
|---|---|---|---|---|
| Design A | 2.00 | $1.04M | 15.0% | Meets |
| Design B | 2.16 | $1.13M | 14.6% | Over capex |
| Recommended | 2.06 | $1.05M | 15.6% | Meets |
A and B are typical feasibility-stage designs. Full search found a higher-IRR option within the same constraints.
What you receive
Everything your board, lender or EPC needs to act on the result, in formats your team already uses.
A clear answer
The recommended design or finding, with the alternatives we ruled out and why.
Bankable numbers
P50 to P99 yield, IRR, LCOE and capex, set out so a lender's engineer can check them.
Working files
A report, an Excel model, PVsyst project files, and DXF and KMZ layouts for CAD and Google Earth.
Kept current
Re-runs when a vendor quote, tariff or grid limit changes. For ongoing work, a tool we build and maintain for your team.
Your engineering team, extended
Take on more sites without adding headcount. From resource data and layout design to energy yield, battery storage, due diligence and operating plant reviews, we cover the full project lifecycle. AI handles the heavy analysis, and our engineers own the results.
Simulation-ready timeseries
Generation timeseries built on real weather history, ready for your PPA, hybrid and dispatch models.
- Irradiance checked across several sources, with temperature profiles
- 20+ years of historical data, not only a typical year
- Generation specific to the location, equipment and design
- Hourly or sub-hourly, in the format your models already read
Deliverables: CSV/Excel timeseries, source comparison
Simulation-ready timeseries
Generation timeseries built on real weather history, ready for your PPA, hybrid and dispatch models.
- Irradiance checked across several sources, with temperature profiles
- 20+ years of historical data, not only a typical year
- Generation specific to the location, equipment and design
- Hourly or sub-hourly, in the format your models already read
Deliverables: CSV/Excel timeseries, source comparison
System configuration optimisation
Every equipment and configuration mix compared on energy and cost, to find the design with the highest IRR.
- Tracker vs fixed-tilt, rooftop and carport options
- Tilt, GCR, module, inverter and DC/AC ratio searched together
- Each option fully simulated, with line-item capex and IRR
- Your current design or EPC proposal as the baseline, so the gain is clear
Deliverables: configuration matrix, IRR ranking, comparison with your baseline
Layout design
Site-adapted layouts for ground-mount and rooftop solar, ready for planning and EPC tender.
- Strings, inverters, MV stations and cable routing designed together and checked by an engineer
- BESS and inverter siting
- Land-use and terrain constraints from SRTM, satellite imagery and stakeholder input
- CAD and PDF layouts for planning and approvals
Deliverables: DXF and PDF layout, 3-D KMZ, block plan, bill of quantities
Energy yield assessment
Bankable P50 to P99 energy yield in PVsyst, with every loss factor documented.
- P50, P90 and P99 from 20+ years of weather data, plus TMY runs
- Soiling, electrical and shading losses, including complex urban sites
- Side-by-side yield comparison across designs
- PVsyst files your team or the lender's engineer can re-run
Deliverables: yield report with loss breakdown, PVsyst project files, P50/P90/P99 table
Battery storage assessment
Battery size and dispatch modelled together with the PV design, tariff and grid limit, so you prove the business case before you commit.
- Solar-BESS pairing, including curtailment recovery under export limits
- Power and energy sized separately, with cost-benefit for each option
- DC-coupled storage and dispatch modelling
- Behind-the-meter storage for peak shaving, demand charges, EV charging and backup
Deliverables: sizing study, dispatch model, business case
Technical due diligence and lender's advisory
Independent review from pre-construction bankability to operational hindcasting.
- Pre-construction and financing: design basis, resource assumptions, equipment and construction readiness
- Bankability reports, risk registers and CP support to financial close
- Acquisition and operations: pre-acquisition review of design, contracts, permits and technology risk
- Hindcasting, yield reconciliation and revised production estimates
Deliverables: IE-style report, risk register, revised P50
200 MW solar + 80 MWh BESS
Pre-construction · lender's technical advisory
Resource basis
Multi-source validated, within 2% of independent estimate
Design basis
Configuration confirmed optimal for site conditions
Equipment
Inverter firmware update required for grid code
Bankability
Risk register complete, CP inputs delivered to lender
Construction
Grid approval pending, 8-week delay risk
350 MW portfolio (3 sites)
Acquisition review · operational + pre-construction
Energy yield
P50 overstated by 3.1% at Site B; revised estimate provided
Contracts
PPA terms and EPC scope consistent with design
Operational review
Hindcast shows 4.2% underperformance at Site A; soiling suspected
Technology risk
Module and BESS technology reviewed, no red flags
Operating plant review and long-term energy forecasts
An accurate view of what an operating plant will produce over its remaining life, for acquisitions, refinancing and asset management.
- Monthly reconciliation of irradiance, energy, PR and availability against expected values
- Root cause analysis of underperformance: soiling, degradation, availability and curtailment
- Satellite-bias correction and yield re-modelling from operational data
- P50 to P99 forecasts over one-year and ten-year periods for the remaining asset life
Deliverables: performance review report, remaining-life P50/P90 forecast, Excel model
Remaining-life forecast · 100 MWp operating plant
| Year | PR | P50 GWh | P90 GWh | P99 GWh |
|---|---|---|---|---|
| 2027 | 78.9% | 158.2 | 151.4 | 145.0 |
| 2032 | 76.4% | 153.1 | 146.6 | 140.3 |
| 2037 | 74.0% | 148.3 | 141.9 | 135.9 |
| 2042 | 71.6% | 143.5 | 137.3 | 131.5 |
| 2047 | 69.3% | 138.9 | 133.0 | 127.3 |
Built from monthly operating data: measured irradiance, energy, PR and availability, reconciled against expected values before forecasting.
The numbers your analysis needs, already in place
What the plant costs and produces, and what its energy is worth. Both sides of the business case are covered from day one, so your project starts with analysis instead of data collection.
Supply side
What it costs and what it produces
Modules
Current Tier-1 datasheets and power bins, across TOPCon, HJT, back-contact, PERC and thin film
Inverters
String, central, MV skids and micro-inverters
Capex and opex
Equipment, balance of system, installation and O&M prices across major regions
Weather and terrain
Irradiance, temperature, terrain and horizon for any site, or your own Solargis and PVsyst files
Your decision
IRRNPVLCOEPayback
Demand side
What the energy is worth
Wholesale prices
Day-ahead prices, solar capture rates and negative-price hours
PPA and retail tariffs
PPA indices, C&I retail prices, import and export tariffs, net metering
Load profiles
Commercial and industrial demand shapes, or your own 8760-hour meter data
Grid limits and curtailment
Export caps and curtailment history, so storage is sized to what the grid takes
Every value carries its source and date
Your BoQ, PAN files and tariffs replace any default
Growing market coverage
What our clients say
"Tomsawyer performed the work competently and met our expectations throughout the project. They showed a diligent approach and attention to details, and worked in a professional manner, ensuring that the tasks were completed on time and to the required standards. We were satisfied with the quality of their work and appreciate the support they provided."
Ignacio Becares
Principal Consultant, DNV AS
"It was a pleasure to collaborate with you, and I really appreciated the fact that you understood our sense of urgency and managed to adapt to our short timelines. The pre-feasibility study documentation was according to our expectations, and you even went beyond with helping us selecting some initial equipment to provide energy estimations."
William Gaillard
Former Wind Head, Carbon Resilience
"The Tomsawyer team was instrumental in supporting the technical layout design for our first utility-scale solar development in the UK, up to securing planning consent. Their sound knowledge of solar optimization enabled the production of an efficient layout, integrating DC-coupled BESS."
Ashley Vandermeer
COO, Naseby Energy Holdings
"Tomsawyer helped us clearly understand the long-term techno-economics of distributed energy asset and sensitivities with respect to configuration changes. They were very collaborative and provided efficient and highly professional support."
Andrew Koh
Managing Director, Megawatts
"What I would say about Tomsawyer is that you are very professional, very dedicated to the work delivering to BBCO Energy. Tomsawyer delivered its advisory service in timely manner, with high responsibility, and caring about customer's problems. I do believe, Tomsawyer will add very good value to its partners/customers by delivering their high quality of work."
Khanh-Loc Nguyen
CEO, BBCO Energy Vietnam
Working with Tomsawyer
Most engagements begin with one site and one question. Many grow from there into ongoing work.
One decision
Whether to proceed, which design to take forward, what to pay for an asset, or why a plant is under-producing. Scoped and agreed before work starts.
A whole pipeline
Ongoing support as your portfolio moves: new sites screened as they arrive, and earlier studies re-run as tariffs, prices and grid offers change.
Alongside your team
Working inside your process and formats, whether for an in-house engineering team or an advisory firm that needs more hands on a deadline.
Engineering that gets projects financed
We've done independent engineering the traditional way. Now our engineers work with AI we built ourselves.
Bishal Madhab
Founder
Bishal started in energy systems research at Carnegie Mellon University, modelling solar and wind power variability, and took that work into applied research at a leading energy policy think tank advising the Indian government, within international consortia including the US-India SERIIUS programme with NREL. His research is published in peer-reviewed journals including Solar Energy.
He went on to co-found a machine learning company forecasting renewable power generation, deployed across 2.5 GW. As Battery Storage Lead at DNV, he helped establish the battery storage advisory practice across Asia Pacific, focused on co-located solar and storage. He then joined Wind Pioneers as its first engineer and helped build the firm's global consulting practice, now active in 40+ international markets.
He founded Tomsawyer in 2019 and built its simulation engine from the ground up. Since then, the team has delivered engineering on more than 50 GW of solar and storage projects.
The team
AI engineers, software engineers and energy engineers with significant experience working with Bishal across multiple GW of solar, wind and storage projects worldwide.
IndiaSingaporeUnited States
Countries where we've delivered engineering