Software · head to head
Helioscope vs Stem Athena
The short version
- Only Helioscope has a free tier, so it costs nothing to try first.
- Each has a real cost: Helioscope licences are single user, so each designer needs their own; Stem Athena stem's site names the product PowerTrack Optimizer, formerly Athena, so the Athena name is retired
- They diverge on capability: Helioscope covers PV system design, Stem Athena covers AI optimization.
Where they differ
Only the attributes on which Helioscope and Stem Athena actually diverge.
| Attribute | Helioscope | Stem Athena |
|---|---|---|
| Starting price | Free | On request |
| Free tier | Yes | No |
| Platforms | Web, Api | Web, Mobile, Api |
| Founded | 2012 | 2009 |
Identical on both: pricing model (subscription), user rating (Not yet rated), category (Unknown).
What each one covers
Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.
Only in Helioscope
- PV system design
- 3D shade modeling
- Performance simulation
- Single-line diagrams
- BOM generation
- Proposal templates
- Component database
- Financial modeling
Only in Stem Athena
- AI optimization
- Energy storage management
- Demand charge reduction
- Grid services
- Solar integration
- Weather forecasting
- Performance analytics
- Remote monitoring
Both cover
- SOC2
- Cloud deployment
What people use each for
The jobs each tool is most often brought in to do.
Helioscope
- Simulating photovoltaic system performance and energy yieldnot Stem Athena
- Laying out commercial solar arrays and producing design reportsnot Stem Athena
Stem Athena
- Optimising dispatch and market participation of battery energy storagenot Helioscope
- Monitoring and reporting on solar and storage asset performancenot Helioscope
- Remote diagnostics across renewable generation fleetsnot Helioscope
Where each one falls short
Documented limitations, not opinions. Every one is a constraint you would hit in normal use.
Helioscope
- Licences are single user, so each designer needs their own
- Projects are capped at 10 a month on both Basic and Pro
- System size is capped by plan, at 1.25 MW DC on Basic and 5 MW on Pro, so a larger array forces an upgrade regardless of project count
- Trackers, LIDAR modelling and API access sit on the higher tiers
- Enterprise is priced per project with no published figure
Stem Athena
- Stem's site names the product PowerTrack Optimizer, formerly Athena, so the Athena name is retired
- No price, subscription fee or contract term is published anywhere on the site
- The optimizer is one component of the wider PowerTrack suite alongside separate EMS, SCADA, Power Plant Controller and Logger products rather than a standalone licence
- Design, procurement, commissioning and operation are sold as managed services separate from the software
Pricing, plan by plan
Helioscope
Free- FreeFree
- 3 projects
- Basic design tools
- Shade analysis
- Professional$95/month
- Unlimited projects
- Advanced shading
- Custom reports
- Enterprise$undefined/month
- Everything in Pro
- API access
- Custom integrations
Stem Athena
On request- Commercial$undefined/custom
- Energy storage optimization
- Demand charge management
- Rate optimization
- Utility$undefined/custom
- Grid services
- VPP management
- Frequency regulation
- Enterprise$undefined/custom
- Fleet management
- Portfolio optimization
- Custom integrations
Which should you pick?
Choose Helioscope if
- You need pv system design.
- You want to start without paying.
- You work on Web, Api.
- You also want 3d shade modeling.
Choose Stem Athena if
- You need ai optimization.
- You work on Web, Mobile, Api.
- You also want energy storage management.
Questions people ask
- Is Helioscope or Stem Athena better?
- Neither clearly leads. Helioscope starts at Free and Stem Athena at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
- Which is cheaper, Helioscope or Stem Athena?
- Helioscope has a free tier; the other does not. Paid plans start at Free for Helioscope and On request for Stem Athena.
- Does Helioscope or Stem Athena run on more platforms?
- Helioscope runs on Web, Api. Stem Athena runs on Web, Mobile, Api.
- Can I use Helioscope for free?
- Yes. Helioscope has a free tier, so you can try it without paying. Stem Athena starts at On request.
- What is Helioscope best used for?
- Helioscope is most often used for simulating photovoltaic system performance and energy yield, laying out commercial solar arrays and producing design reports. Of those, simulating photovoltaic system performance and energy yield and laying out commercial solar arrays and producing design reports are not what Stem Athena is typically brought in for.
- What can Helioscope do that Stem Athena cannot?
- Helioscope covers PV system design, 3D shade modeling, Performance simulation, Single-line diagrams. Stem Athena covers AI optimization, Energy storage management, Demand charge reduction, Grid services. Both handle SOC2, Cloud deployment.