70% efficiency is nothing to sneeze at. Stewart Island, which they envision serving with a commercial system, is powered by diesel generators with a cost of electricity of ~$1/kW-h. It's about 50km across the water from Bluff, where there is a surplus of energy due to a large aluminum smelter served by a dedicated hydroelectric plant.
With only about 300 people, the community on Stewart Island can't justify an undersea cable. But a microwave power beaming system could be built for much less, and supply energy much cheaper (and greener) than burning diesel.
Island sited renewables (wind and solar) are probably a better option than high power radar through free air. Two wind turbines are enough to displace half of the diesel fired generation. Just need more turbines, solar, and some batteries.
> The Provincial Growth Fund is putting $3.16 million towards building two wind turbines on Rakiura / Stewart Island
> Mr Parker said building an initial two wind turbines as part of the island's power generation network was the most economic and environmentally acceptable option.
> "It provides a renewable energy source. It is estimated to reduce diesel use on the island by half, which will enable the price of electricity to be stabilised."
A number of studies have been done over the years exploring wind, solar and other alternatives. Unfortunately, they aren't perfect. non, including the two turbine solution, comes even close to providing the energy required and will still require diesel generation and LPG on the island. there is no more room for anything beyond 2 turbines on the island so it a partial solution with no scalability. Emrod can provide x5 the current energy required on the island, cheaper, replacing Diesel and LPG, future proofing supply continuity, with a far smaller environmental footprint.
> where there is a surplus of energy due to a large aluminum smelter served by a dedicated hydroelectric plant.
This smelter is also about to shut down in August 2021. So now there's going to be a huge surplus of electricity way down south (the smelter uses ~13% of the country's total electricity!), with the big city way up north.
This is great to hear, that extra power (if the South<->North New Zealand HVDC Interconnect has the capacity [1]) will help push out New Zealand's last coal plant on the north island and possibly some of the gas generation [2].
We'd have to build a lot (billions) of new distribution infrastructure to get the Manapouri power to Auckland.
There are a lot of ideas circulating about what to do with the Tiwai plant, including setting up a Tesla factory (it has a deep water port handy). There just happens to be a source of the purest silicon sand in the world nearby, so one intriguing option is to set up solar panel production, which given the hydro power supply would have very high sustainability credentials.
> However, a key drawback of this “power-to-gas-to-power” route, if electrolysis is used for hydrogen production, is the round-trip efficiency, which is “around 45%,” it says. The report provides an example to illustrate the cost penalty per MWh associated with the power-to-gas-to-power route: “Hydrogen generation from low-cost renewables at $25/MWh with a capacity factor of 50% yields a cost of $1.70/kg of hydrogen produced. Storing this hydrogen underground will add about another $0.30/kg, thus the hydrogen costs $2/kg. If this hydrogen is used to generate power, the resulting cost is $100 to $200/MWh. In ideal conditions (e.g. a CCGT turbine at 60% utilisation), the cost is $100/MWh, while simple-cycle turbines at 25% utilisation would deliver power at $200/MWh.”
> Still, the report is optimistic. Because hydrogen production costs will drive up to 80% of total power generation costs (Figure 3), if the technical feasibility of a 100% hydrogen turbine is proven, the capital expense of hydrogen turbines could “rival that of natural gas turbines by 2030,” it says. For now, however, “companies should use hydrogen-based power for high-value flexible generation first, and two, hydrogen baseload power generation for deep decarbonisation in situations with constrained renewables potential will require strong policy support.”
Yes, it's essentially the same architecture: two large phased arrays pointing at each other. The terrestrial technology development could transfer to the space application, or vice versa.
With only about 300 people, the community on Stewart Island can't justify an undersea cable. But a microwave power beaming system could be built for much less, and supply energy much cheaper (and greener) than burning diesel.