lecture 12: sustainable & renewable energy 1

Renewable energy?

energy forms that exploits essentially limitless energy sources from Sun, Earth, and its moon

Renewable energy teachnologies>

exploitation of critical elements as well as lots of copper

How much did renewable energy account for global electricity generation in 2023

30.3%

What are the cheapest sources of renewable energy?

wind

solar

How much of Ireland’s energy is generated via renewables?

40%

Where in Europe has the most potential for wind energy?

N Europe: Irish and North Sea

S Europe: Aegean sea, south France, Spain

What is the wind energy capacity factor?

~30%

advantages of onshore wind energy?

• cheaper foundations + installations

• cheaper + easier to integrate into electricity network

• cheaper + easier to access for operation + maintenance

Disadvantages of onshore wind energy?

• environmental damages

• visual impact

• noise pollution

• obstructions

• planning objections and restrictions

• limited availability of suitable land

• land disputes

advantages of offshore wind energy?

• higher more constant wind speeds

• larger structures

• fewer objections to construct

Disadvantages of offshore wind energy?

• more expensive to construct, operate, + maintain

• high risk of damage

• more distant from electricity network

Wave energy?

waves, tides, currents, thermal gradients, salinity gradients

tidal energy capacity in 2023?

41.2MW

Test sites in Ireland

• LiR National Ocean Test Facility in Ringaskiddy, Co. Cork 

• Marine and Renewable Energy Test Site located within the confines of Galway Bay 

• Atlantic Marine Energy Test Site (AMETS) off the coast of Belmullet, Co. Mayo 

wave energy

extracts energy from motion of waves

Process of extracting

Wave bob

Pelamis or Ocean energy Buoy

Energy at 0-100m water depth

12.5GW - 13.6GW

100-200m water depth

15GW - 17.5GW

Currently immature technology

• many different concepts

• needs further technological advancements

• only tested on a few scale-models

Technological barriers to overcome

• reliability

• weather problems

• biofueling

• maximising power output

La Rance Tidal Power Station (France) 

• Opened in 1966 as the world’s first tidal power station 

• Total installed capacity: 240 MW with a capacity factor of c.24% (averages 57MW) 

• It supplies <0.1 % of the electricity demand of France 

• Cost: €94.5 m (1967) – about €580m (2009) 

• It generates power on both ebbs of the tide

Sihwa Lake Tidal Power Station (S. Korea) 

• the world's largest tidal power 

• installation, with a total power output capacity of 254 MW. 

•  Completed in 2011, it surpassed France’s 240 MW Rance Tidal Power 

• Station which was the world's largest for 45 years 

• Ten 25.4 MW submerged turbines are driven in an unpumped flood generation scheme. Power is generated on tidal inflows only (one-way power generation) 

Strangford Lough (N. Ireland) 

• Installation completed in 2008 

•  SeaGen S 1.2 MW turbine (25m depth) 

•  Power output: 6 GW per year (1,500 homes) 

• The System was removed in 2017. Siemens sold the company and technology to a rival company in 2015. 

Mutriku Wave Energy Plant 

• Location: Basque Country, Spain 

• Construction start: 2006 / Operation started: 2011 

• Installed capacity: 296 kW to power 100 households (small!) 

• Cost: €2.3m 

• Technology: OWC (16 air chambers / turbines) 

• No moving parts – compress air to spin turbine  

 

Solar energy Technologies

• Photovoltaic (PV) systems (Solar cells convert sunlight directly into electricity) 

• Solar hot water (flat-plate thermal collectors installed facing south on a rooftop) 

• Solar electricity (concentrating solar power systems)  

How much have solar panels decreased in price since 2010?

82%

First generation biofuels

• Compete with food production, driving up world market prices especially in countries using maize as a staple. 

• Rainforests and habitats destroyed in order to grow palm oil and sugar cane. 

• Land use changes release CO2 stored in soils. 

•  Not enough land to make a meaningful contribution. 

•  Extra demands on fertilizers and water. 

Second generation biofuels

• Use woody parts of plants (e.g. stalks and leaves from plants grown for food production). 

• Energy yields are higher, particularly outside tropical regions. 

• Economics improving but still a lot to do 

third generations biofuels

• Include low-lignin trees; genetically modified corn to break cellulose in leaves. 

• Interesting research on algal-based and seaweed-based fuel production 

• Embryonic research stage. 

What is a problem with solar energy supply?

the peak energy generation does not match peak demand times

What are energy storage options?

• Pumped Storage Hydroelectricity 

• Compressed air