On 30 September Virtus Solis and Brae Systems announced a twenty-year power purchase

agreement for 100 MW of orbital solar power delivered to a receiving station in Illinois.

The release's own annual energy figure, 876,000 MWh, is 100 MW multiplied by all 8,760

hours of a year.

That is a capacity factor of exactly one. The expansion option in the same release carries

the same property: 250 MW and 2.19 million MWh, which is 250 multiplied by 8,760 to the

digit. Both figures are documented, in the sense that they are published by the parties

themselves. Neither is a measurement, and neither is an estimate of what will arrive at a

rectenna in Illinois.

The energy figure is the nameplate figure

The release also states a 99.9% uptime target. Those two numbers do not describe the same

year. Take 99.9% of 8,760 hours and you get 8,751.2, which at 100 MW is 875,124 MWh. The

annual figure the release publishes is 876 MWh higher, because it was not derived from the

availability target at all. It was derived from the nameplate.

The gap is small and the point is not that 876 MWh matters. The point is the method. A

terrestrial contract states contracted capacity, then an availability obligation, then an

expected annual delivery that is strictly less than the product of the first two, because

somebody has subtracted scheduled maintenance, forced outage and conversion loss. Here the

subtraction step is absent, and the word used for the result is "delivering".

There are specific reasons an orbital number cannot be 8,760 hours. According to pv

magazine USA, reporting on 1 October 2026, the architecture is a Molniya-type highly

elliptical orbit with a twelve-hour period, each orbital power station visible from the

ground site for about eight of those twelve hours, and three stations required for a

continuous supply. BeamDesk has not independently verified that description against a

first-party Virtus Solis publication, because the company's own news index has not been

updated since 2024. If it is right, three stations at eight hours each is twenty-four

hours with zero margin: the architecture as described has no spare satellite, and any

station out of service is a gap in a product sold as baseload. That is before eclipse

seasons, before rain and atmospheric absorption on the downlink, before handover between

stations, and before DC conversion at the receiver.

None of this makes the contract dishonest. Rated power times hours is a perfectly normal

way to express a ceiling. It is the wrong way to express a delivery, and a reader who

takes 876,000 MWh as a forecast has been handed the single most misleading collapse

available in this field: rated quoted as though it were average.

It is the second space solar PPA, not the first

The coverage calls this the first commercial orbital solar power purchase agreement. It is

not, and the earlier one is worth reading because it did the arithmetic better.

On 3 December 2009 the California Public Utilities Commission issued Resolution E-4286,

approving cost recovery for a power purchase agreement between Pacific Gas and Electric and

Solaren Corporation. The terms in the resolution are 200 MW, a fifteen-year contract, 1,700

GWh per year, and a commercial operation date of June 2016.

Two hundred megawatts across 8,760 hours is 1,752 GWh. The 2009 contract wrote 1,700. The

discount is three per cent, which is far too small to represent a real availability model

for a beamed link, but it is not zero, and it tells you somebody in that transaction

distinguished a ceiling from a delivery.

The Commission also wrote down what it was approving. The resolution describes a

"first-of-its-kind space-based solar project" and says the Commission had previously

approved renewable contracts only for "projects that utilize commercialized or

pre-commercialized technology, not technologies that are still in the research and

development stage". It conditioned approval accordingly: PG&E was barred from relying on

the Solaren project for procurement planning until construction actually began.

Solaren's own account of what happened next, published on its website on 29 January 2021,

is that it could not obtain commercial financing, and that "In 2015, Solaren and PG&E

mutually agreed to forgo the power contract". No power was ever delivered.

The useful difference between 2009 and 2026 is not optimism. It is that the 2009 deal

passed through a regulator who insisted in writing that an unbuilt orbital project could

not be counted on, and the 2026 deal is between two private companies with no such referee.

Latitude Media reports that the agreement carries technical and financial milestones on both

sides and that Virtus Solis's founder expects first power around 2030. BeamDesk has not

independently verified either statement; neither appears in the companies' release.

The hard part is not the meter

A power purchase agreement settles on measured delivered energy, so it is worth being

precise about which part of that is actually missing for a beamed link.

The meter is not missing. Direct current out of a rectenna is measurable with ordinary

revenue-grade instruments, the same as any inverter output. What is missing is everything

the contract has to say around it: where the delivery point sits, how availability is

defined when the transmitter is in orbit and the receiver is not, and who carries a

shortfall when the beam, the weather and the receiver are three separate failure modes with

three separate owners.

There is no published method for that apportionment. The ITU-R Recommendation covering this

class of system, SM.2151-0, is still the only edition in force on the ITU's own editions

page, and its title scopes it to "wireless power transmission via radio frequency beam for

mobile/portable devices and sensor networks". A hundred-megawatt orbital link is not the

thing that document was written about. On the measurement side, IEEE P63480, titled

"Standard for Assessment of Human Exposure to Electromagnetic Fields from Radiative Wireless

Power Transfer Systems", has been an Active PAR since 29 June 2023 with no published draft,

and in any case it addresses exposure assessment rather than revenue metering.

Exposure is where the published numbers do exist, and they bind on power density rather

than on contracted megawatts. ICNIRP's 2020 radiofrequency guidelines set a general public

reference level of 10 W/m² incident power density above 2 GHz, averaged over 30 minutes and

the whole body, with a 40 W/m² local limit over 6 minutes. IEEE C95.1-2019 is the parallel

instrument and remains an active standard. Neither is a constraint on how many megawatts a

contract names. Both are constraints on the beam's footprint, and no spot size or edge power

density for a 100 MW link has been published by anyone in this story.

What is actually being demonstrated

The hardware step beneath the contract is documented and it is small. The US Department of

Energy's NEPA categorical exclusion record CX-270832, dated 16 September 2025, describes the

Virtus Solis wireless power transfer project as a four-metre phased array transmitting over

one kilowatt of radio frequency power across 200 metres to a four-metre receiving array, at

"minimum 70 percent end-to-end efficiency from source to delivered direct current". The

September release points at March 2027 for "a public demonstration in which it expects to

yield record Wireless Power Transfer (WPT) efficiencies", and publishes no figure for them.

Set that beside the contract. One kilowatt becomes one hundred thousand kilowatts. Two

hundred metres becomes the slant range to a highly elliptical orbit: a twelve-hour period

implies a semi-major axis near 26,600 km, and on a Molniya-like eccentricity that puts

apogee in the region of 40,000 km altitude. That last figure is an estimate derived from the

stated period, not a published Virtus Solis number. pv magazine USA puts an intermediate

step in between, a 100 kW pilot in low Earth orbit in roughly twenty-four months.

So the published ladder is a kilowatt on the ground in 2027, a hundred kilowatts in orbit

around 2028, and a hundred megawatts around 2030. Each rung is three orders of magnitude or

a change of regime, and only the first has a government record attached to it.

The case for taking it seriously

A milestone-conditional PPA for unbuilt capacity is a real instrument and not a press

release with a number in it. It gives a developer a named counterparty, which is what

project finance asks for first, and it tells you a buyer with a specific load profile has

done enough diligence to sign something. Buyers of continuous power for compute have a

genuine reason to look at orbit, because the thing they are short of is firm supply rather

than nameplate.

The date worth putting in a calendar is March 2027. A measured end-to-end efficiency at 200

metres, published with its method, would be the first number in this entire story that is

not a projection. Until then the honest description of the agreement is that two private

companies have agreed terms for electricity that nobody has yet generated, metered or

delivered, with an annual energy figure computed as though the sun never set and nothing

ever broke.

What would change my mind

Publication of the contract's availability structure. If 876,000 MWh is a stated ceiling

with an availability schedule and a shortfall remedy underneath it, then the release is

loose and the agreement is sound, and the criticism above lands on the press release rather

than on the deal. One term sheet summary defining the delivery point would settle it.

A first-party availability model from Virtus Solis: eclipse seasons, handover between

stations, atmospheric loss at the Illinois site, with an annual energy estimate that is

visibly below rated power times 8,760 hours. That would show the subtraction was done and

simply not published.

A measured DC-to-DC efficiency at or above 70% across 200 metres at the March 2027

demonstration, with the method stated. That makes the kilowatt rung real, and it would move

my scepticism from the arithmetic to the much more interesting question of whether the

scaling holds.

What would not change my mind is more coverage of the same release, or a larger contract

announced before a measured figure exists.

Sources