In a bid to lower energy costs, meet growing demand with sustainable power, and reduce toxic emissions, the UK is turning to renewables to replace its existing power systems now more than ever. From a technical perspective, however, the path to implementation remains lined with challenges...
Are Zero Carbon Emissions Viable?
Renewable energy comes from a variety of sources, including sunlight, heat, wind, and waves. The main 2 benefits of renewable energy are that it doesn't run out, and that it doesn't give off greenhouse gases (unlike petrol and diesel).
Experts believe wind and solar energy are some of the most viable options for supplementing the power grid, which is more cost-effective than fossil fuels in the long-term. Weâll now focus on these 2 renewables and discuss the benefits and challenges involved in implementing them on a large scale.
A large wind farm project (based in Galicia, Spain). Image courtesy of Pixabay.
Wind power is one of the cleanest and most renewable sources of energy, as it transforms mechanical energy into electric power through turbine blade rotations alone.
The process powers residences, factories, agricultural facilities, and many other establishmentsâand with around 94 wind farms already commissioned in Europe, there is a tremendous opportunity for more stable and cost-effective power generation still. A joint study by the University of Sussex and Aarhus University, Denmark concluded that nearly half of Europe can be utilised for wind energy generation.
Unlike in the 1950s, when the cost of solar power per watt was a steep $1,910, today it costs less than $0.80. Ordinarily, wind turbines store charge in their corresponding batteries, which then supply power for commercial consumption. When integrated into power grids, they can help minimise the energy demand from utility companiesâa technique called peak shaving. Moreover, wind power farms generally have low operations and maintenance (aka O&M) costs.
According to data from ISET, aka the Institut fÃ¼r Solare Energieversorgungstechnik (nowadays called Fraunhofer IWES), operational expenditure for wind turbines reduces as the relevant capacity increasesâwith 800 to 100kW turbines having 15% less operational costs than 420 to 490kW systems. Going by this data, wind energy can be a significant energy source in the UK.
A large array of photovoltaic (PV) cells on a sunny day. Image courtesy of Pixabay.
Solar energy is the most prominent type of renewable energy. It harnesses radiation from the sun to generate electricity in photovoltaic (PV) cells. Due to their large power installations that hold a vast assemblage of PV cells, solar farms can augment an existing power grid or even serve as a standalone system.
Such large-scale setups can be land-based or located offshore, with a vast number of PV cells interconnected to increase the power outputâenough to power small communities, or in some cases even cities.
Factoring in the most recent advancements in manufacturing technology, PV material is becoming significantly cheaper to produce. A good example is Perovskite, a cheaply-sourced carbon material with a conversion efficiency that reaches up to 23.7%. In 2018, Dr Zonghao Liu (a scientist at the Okinawa Institute of Science and Technology Graduate University, Japan) demonstrated the significantly increased lifespan of a solar cell using a 1-micron thick layer of the material. Like wind turbines, solar systems also require adequate energy storage solutions. Deep-cycle batteries are used to store the energy produced during the day due to the frequent charge/discharge cycles.
The Road to Implementation
There are a host of fiscal and technical considerations involved in implementing renewables on a national scale. Hereâs a look at some of the most critical aspects:
The Intermittency Issues of Renewables
One of the main reasons why fossil fuels are still the predominant energy source is that they are easily quantifiable. For instance, many industry professionals can accurately estimate the time it will take for a litre of diesel to power a generatorâs combustion engine. Renewables, such as the said solar energy and wind installations, on the other hand, are affected by external factors beyond the control of engineering design.
For example, the amount of solar radiation that a solar panel receives in a day fluctuates, depending on prevailing weather conditions, the location of the PV array, and so on. Immediate implications are that electric power might not be available when needed, and/or it may vary in terms of its volume and the time it will take to achieve it. Such issues of course defeat an energy systemâs main purpose, which is to provide reliable power.
Altogether, as renewable systems are increasingly relied on to produce more electricity, they each require a significant energy storage capacity to accommodate the demands.
The Cost Considerations
Another important aspect that could increase the cost of implementing a renewables-fuelled or assisted power grid is energy storage. Large solar installations and wind farms require a prodigious amount of battery capacity. This challenge introduces additional costs to the project as current battery manufacturing techniques are expensive. A former chancellor under Theresa Mayâs government, Philip Hammond, believes the cost of switching to a renewables-powered grid by 2050 will amount to a whopping Â£1 trillion.
The Environmental Impact
Although cleaner than hydrocarbon-based fuels, renewables, such as solar, wind, and geothermal, indirectly impact the environment in significant ways. One critical area is in battery production. The high-power density batteries contain toxic elements such as lead, which can acutely or chronically poison people, in scenarios where the substance leaches through the soil and into public water supplies.
Wind power, moreover (albeit one of the cleanest sources of energy), exerts demand for extensive land use, which can encroach on the natural habitats of plants and animals. The technology also contributes to noise pollution in nearby settlements.
A close-up of a wind turbine in operation. Image courtesy of Pixabay.
All in all, with the renewable technologies currently available, national-scale integration may indeed be feasible in the UK in the next few decades. As technology advances, renewables are becoming more efficient and cheaper to manufacture, as weâve seen with perovskite-based solar cells.
Ultimately, with enabling legislation from the UK government already underway, the question is no longer âhowâ, but âwhenââand the country has pegged such a time at 2050.