• • • ENERGY EFFICIENCY • • •
Accumulating small savings is having a large total effect on carbon reduction
Armin Anders, co-founder & VP business development at EnOcean, says major energy sources, for generations now, have been fossil-based and therefore laden with carbon-based compounds that combine with oxygen when burned to create those dangerous greenhouse gases – they also emit other toxins as well as particulates that are damaging to health
or some time now, we have been pursuing the goal to transition our energy sources from these traditional fuels to renewable sources. Springing to mind are perhaps the prominent of these, wind and solar energy with 3.37 terawatts of installed capacity now in operation worldwide, according to Statista. Other sources include geothermal energy harboured within the earth’s core and wave energy induced by the gravitational effect of the moon. Taking advantage of these sources is all about energy harvesting: converting that ambient energy into a form that is usable for human purposes. This is usually electricity and is predominantly produced by the large renewable- energy farms, both wind and solar, being installed in large numbers and across large areas of the earth’s surface.
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These energy sources are quite satisfactory in many ways: today’s power electronics and conversion technologies can turn those few electron volts from PV panels, or the irregular, harmonic-laden waveforms from a wind turbine into usable electrical power.
This may be a DC supply at a suitable voltage for powering loads directly, or for charging battery storage. Or it may be a high-quality AC output at a suitable voltage and frequency to feed in to the grid.
Making less go further One aspect that is less favourable, however, is scarcity. While there may be an abundance of sun and wind, and perpetuity is not in doubt, the quantity of electrical energy produced is quite low in relation to global demand, and generation is only possible when enough sun or wind is present. These times are not predictable or regular. There are several practicable responses to this problem. One is storage: to make as much electricity as possible while the sun shines (or the wind blows) and store this in a battery array to be used later when ambient energy sources are not present.
This is as valid in small domestic micro- generator applications as in utility-scale applications that integrate large grid-connected battery arrays. Some suggest these could be built
from electric-vehicle batteries that still have about 80% of their capacity but are deemed to be unsatisfactory to continue their life on the road. Grid-connected storage is a hot topic with great potential, although best practices are yet to be finalised and much work remains to be done to install and connect enough storage.
The other side of the coin lies in reducing overall energy demand to meet the increasing installed capacity for renewables. There are several ways to do this, including developing more efficient appliances, improving power-conversion efficiency, and adopting more efficient processing techniques such as moving AI inference to edge devices and IoT sensors. We could also consider authoritarian measures such as enforcing limits on personal EV- mileage quotas through measures such as battery- charging caps or geofencing.
Smart buildings
It is well known that a large proportion of the world’s energy is consumed in buildings, to power lighting systems, room heating, and water heating. Historically, these have been powered through a
36 ELECTRICAL ENGINEERING • JULY/AUGUST 2023
electricalengineeringmagazine.co.uk
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