# Assessing the Economic and Environmental Viability of Undaria pinnatifida Sporophylls as Sustainable Cattle Feed in South Korea

## TL;DR

This study explores using Undaria pinnatifida sporophylls, a seaweed by-product, as cattle feed in South Korea to reduce waste and improve feed security, finding it can be economically viable with strong carbon pricing.

## Contribution

The study introduces a partial equilibrium framework to assess the economic and environmental viability of recycling seaweed by-products into Hanwoo cattle feed under Korea’s carbon pricing system.

## Key findings

- Without environmental benefits, processing costs of Undaria pinnatifida sporophylls outweigh savings.
- Methane abatement benefits under Korea’s carbon trading system generate net economic benefits at higher carbon prices.
- Effective carbon pricing and subsidies are essential for long-term viability of seaweed by-product recycling.

## Abstract

Seaweed aquaculture generates substantial amounts of by-products that are often discarded, creating both waste and environmental challenges. In Korea, the sporophylls of sea mustard (Undaria pinnatifida) represent a major by-product of seaweed aquaculture. Rather than being treated as waste, these by-products can be recycled as feed for Hanwoo cattle (Bos taurus coreanae), thereby promoting circular resource use and strengthening feed security. This study evaluated the economic and environmental effects of such recycling by considering processing costs, savings from avoided disposal and reduced grain imports, and the benefits of methane abatement. The analysis showed that, without accounting for environmental benefits, costs exceeded savings. However, when methane abatement was valued according to Korea’s carbon trading system, net benefits emerged, particularly at higher inclusion levels, but only when carbon prices were sufficiently high. These results suggest that seaweed by-products can contribute simultaneously to climate mitigation and feed resilience. Policy instruments such as carbon pricing and targeted subsidies will be essential to ensure long-term viability for producers.

This study analyzed the economic feasibility of utilizing Undaria pinnatifida sporophylls (UPSs), a major by-product of seaweed aquaculture, as feed for Hanwoo cattle. It employed a partial equilibrium framework to quantify processing costs, avoided disposal costs, substitution savings from reduced grain imports, and monetized methane abatement benefits, calibrated with national statistics on Hanwoo production and feed use for 2022–2024. The analysis revealed that, in the absence of environmental valuation, additional collection, transport, and drying costs (KRW 25,714–102,857 per head at 0.25–1.0% inclusion) outweighed savings from disposal avoidance and import substitution. When methane abatement was priced under Korea’s Emissions Trading Scheme, however, net benefits emerged, ranging from KRW 22,757 to 40,859 per head, with welfare gains of KRW 19,108 million at 1.0%. Sensitivity analysis confirmed a strong dependence on carbon prices: benefits were substantial at KRW 40,000 per ton of CO2, remained positive yet relatively limited at KRW 20,000, and shifted into negative territory at KRW 10,000. These findings demonstrate that UPS feed utilization can advance climate mitigation and feed security, provided it is supported by effective carbon pricing and producer-oriented policies.